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The scope of this standard is to address the major steam temperature control subsystems in boilers with steaming capacities of 200,000 lb/hr (25 kg/s) or greater. These subsystems include, but are not limited to, superheat temperature control and reheat temperature control. Specifically excluded from consideration are controls associated with fluidized-bed, stoker-fired furnace combustion units and mud drum desuperheaters.


The purpose of this standard is to establish the minimum requirements for the functional design specifications of steam temperature control systems for drum-type and once-through type fossil fuel power plant boilers.

A Word from the Chairman

The edition of ANSI/ISA-77.44.01-2007 (R2013), Fossil Fuel Power Plant - Steam Temperature Controls, was prepared by the individuals on subcommittee ISA77.44 who contributed to the production of ANSI/ISA-77.44.01-2000, Fossil Fuel Plant Steam Temperature Control System - Drum Type and ANSI/ISA-77.44.02-2001, Fossil Fuel Plant Steam Temperature Control System - Once-Through Type. The purpose of combining these two documents was to consolidate related text.  The content has been organized and updated per current practices.

This document has been prepared as part of the service of ISA toward a goal of uniformity in the field of instrumentation.  To be of real value, this document should not be static but should be subject to periodic review.  Toward this end, the Society welcomes all comments and criticisms and asks that they be addressed to committee chair, Daniel Lee.

For more information, please contact

Eliana Brazda
ISA Standards Administrator
(919) 990-9228